Removable inflatable protective closure for jet engine



May 8, 1956 B. soKoL ETAL REMOVABLE INFLATABLE. PROTECTIVE CLOSURE FOR JET ENGINE 2 Sheets-Sheet 1 Filed June 21, 1954 INVEN TOR. Bel 11min Sokol and BY August Di Florio flag S. u-QZH ATTORNEY.

May 8, 19 B. SOKOL ET AL REMOVABLE INFLATABLE PROTECTIVE CLOSURE FOR JET ENGINE Filed June 21, 1954 2 Sheets-Sheet 2 1 "I Ill/l/I/ III I u 5 ll j INVENTOR.

Z Bery'amz'n Sake! and By August 01' F/orio flw. WTLZI l ATTDRNE Y.

REMOVABLE INFLATABLE PROTECTIVE CLOSURE FOR JET ENGINE Benjamin Sokol, Valley Stream, and August Di Florio,

. Rosedale, N. Y., assignors to Republic Aviation Corporatlon, Sulfolk County, N. Y., a corporation of Delaar 1 Application June 21, 1954, Serial No. 437,930 Claims. (Cl. 60-39.09)

This invention relates generally to temporary protective covers or closures and more particularly to an'inflatable member of flexible, resilient material which may be shaped and formed to snugly close an aperture in the housing of a mechanism while it is being worked on, transported,

stored or otherwise not in operation, to prevent hardware, metal scrap, dirt and other foreign matter from entering the aperture and ultimately impairing the operation of the mechanism.

Among its several objects the present invention has in view a member of the type set forth above that is inexpensive and which lends itself to quantity production. At the same time the invention proposes a protective closure which may be easily installed in, and removed from, its operative position in the opening for which it is designed and adapted and which, when once installed, is not readily removed by any foreseeable accidental means, but requires its intentional removal. Moreover, when properly installed it virtually seals the opening to prevent the ingress of dirt, dust and even the finest foreign substances.

; It is also withinthe contemplation of the instant inven tion to provide such a protective closure that will not damage or impair the mechanism which it is intended to protect in the event it comes into engagement with such mechanism.

With the above and other objects in view, as Will be apparent, the invention consists in the construction, combination and arrangement of parts all as hereinafter more fully described, claimed and illustrated in the accompanying drawings, wherein:

Fig. 1 is a front elevation of the forward or air intake end of a jet engine for aircraft, none of the internal .mechanism of which is shown being contained within the engine housing;

Fig. 2 is a front elevation of a protective closure or tube constructed in accordance with this invention and designed to" fill and se'alingly close the open end of the engine housing as shown in Fig. 1; Fig. 3 is a section taken along line 33 of Fig. 2 to show the manner in which localized portions of the walls of the tube of the protective closure are integrally joined to form a plurality of spaced partitions disposed substantially transversely of the tube;

Fig. 4 is a section taken along line 44 of Fig. 2 to show the air inlet means by which the tube may be inflated and deflated-together with means for closing and retaining the'air' inlet-means to prevent the leakage of air from the tube';and, 1

Fig. 5 is a longitudinal section of one symmetrical half of the engine housing shown in Fig. 1 and of the protective closure; or tube illustrated in Fig. 2 inflated and installed therein to show the cooperation between the inflated tube 2,744,382 Patented May 8, 1956 mechanism may be damaged, or have its operation impaired thereby. However, it has particular utility in connection with jet engines employed in aircraft both at the time of the original installation thereof in the airframe and subsequently during themaintenance and repair of the aircraft or engine.

nary work thereon by mechanics and workmen.

In the case of original installation, for example, it is the practice'in the industry for the airframe manufacturer to receive the complete jet engines individually packed and crated from the engine manufacturer. As the airframe is being built and assembled, the engine along with other assemblies and subassemblies is installed into the air: frame. Just prior to such installation the engine is uncrated and for the first time, as far as the airframe manufacturer is concerned, exposed to handling and prelimi- From the time when it is installed in, or assembled with, the airframe until the finished aircraft comes oif the final assembly line, days and even weeks usually elapse during which time construction and work is being performed onthe aircraft and the engine. I

Experience has shown that by the time the aircraft leaves final assembly and is prepared for its initial test, bolts, screws, rivets, hardware, and even tools accidentally enter or are drawn or sucked into the engine hous-' ing where serious'a'nd irreparable damage to the components thereof has resulted. As is well known, jet aircraft engines are not only expensive but are also precision made and many of the internal working parts thereof are sensitive or fragile. Damage to these parts is usually cumulative in that one precision element being thrown out of phase wth complementary and coacting elements results in the ineffective and inefiicient operation of the engine as a unit and even renders it completely inoperative.

It-is toward the solution of the above as well as other final assembly of the aircraft and until initial test opera- I eration of the engine, it will either prevent such operation due to lack of air or be sucked into the. engine and be itself destroyed rather than causing damage to any components of the engine, since it embodies no hard or metal parts.

Referring more particularly to the drawings, 10 designates the housing or outer wall of a jet engine for aircraft. The forward or air-intakeend of the housing or wall 10 1's open as at 11 to permit the free and unrestricted passage of air to the working components of the engine 'such as the turbine and for ultimate use in the combustion chamber of the engine. Adjacent the forward or outer end of the engine housing 10, and disposed within'the opening 11, is a'frame orspider 12. This spider 12 comprises a central ring or annular bearing 12' organized and arranged to surround the engine hub 13 and a plurality of radial webs or spokes 13 fixed to andprojecting outwardly therefrom. Each spoke 13' is secured to the inner wall of the engine housing 10 in any conventional and well-known manner such as for example by welding,

rivetingetc. Thus theforwardopening- 11 in the engine 3 housing is, in effect, divided into openings or air inlets 14.

In order to close the opening 11 to prevent the influx of foreign matter to the working parts or components of the engine, a protective closure is proposed. This closure consists of an inflatable, flexible and resilient tube 15. The tube comprises a pair of identical sheets of rubber, vinyl resin or an equivalent material, which are generally shaped to conform to shape and area of the air inlet opening 11 of the engine housing 10. Each of these sheets is pierced with a central aperture 16 having a diameter substantially equal to that of the annular bearing 12' disposed on and about the engine hub 13 as aforesaid. Each sheet is then cut transversely, as at 17, whereby to provide a radial slit extending from the central aperture 16 to the outer peripheral edge of the sheet. The sheets are then superimposed one upon the other with the inner peripheral edges thereof which define the openings 16 therein, the outer peripheral edges and the radial slits 17 respectively in registration. With the sheets 15 in this position heat and pressure are simultaneously applied in any well-known and desired manner to all of these edges of both sheets. In this way the material comprising these sheets is vulcanized or sealed into a homogeneous, unitary construction whereby a tubular, inflatable member is created.

In the case where the sheets comprising the tube 15 are vinyl, it is preferred to electronically seal them to each other. This is generally accomplished by pressing the sheets together between a pair of metal plates or clamps in any convenient and desired manner and sending a high frequency current through the plates so positioned. This causes the registered edges of the vinyl sheets to fuse or melt and unite into a homogeneous unit. In any event, however, the method of joining or sealing the sheets one to the other, per se, forms no part of the present invention. It is only important in so far as the invention requires that the sheets be so united as to produce an airtight tube 15 which is inflatable.

With the sealed ends of the tube 15 defining the radial slit 17 positioned to overlie and be coextensive with one of the radial spokes 13 of the spider 12, pressure and heat or current as the case may be are applied to portions of the tube which are disposed in positions corresponding to and overlying each of the remaining spokes 13' (here illustrated by way of example as numbering three) of the spider 12. The inner or adjacent walls of the tube 15 in this area are thus joined, i. e., vulcanized or electronically sealed one to the other, as at 18, so as to become, in effect a unitary, homogeneous construction comparable in every respect to the seals about and along the defining edges of the sheets as above described. It is to be noted that each of the seals 18 is disposed substantially in the transverse center of the tube 15 whereby that portion of the tube at either end of the seal 18 is in open communication with the remainder of the tube 15. In short, the seal portions 18 are, in effect, comparable to spot-welds being localized to the transverse center portion of the tube 15 and are each generally elongated in shape to conform more or less to the shape of the spokes 13' of the spider 12. These seals or welds 18 divide the tube 15 into a series of intercommunicating chambers each of which corresponds to and enters and fills a space 14 between adjacent spokes or webs 13' of the spider 12.

A single sheet or flap 19 of material identical to that of the tube 15 is sealingly attached to the tube at and along one of the ends thereof at the radial slit 17 whereby the major portion of the flap 19 is disposed in overlapping association with the other end of the tube 15. This attachment or connection may be accomplished by vulcanizing or sealing the material as set forth and described above. In addition, the flap 19 extends radially of the tube 15 a relatively short distance beyond the limits thereof.

While the method of constructing the tube 15 has been described step by step, it is to be understood that a desired and equally acceptable construction may be attained regardless of the order in which these steps are taken or even if the tube 15 is formed in a single operation or step without departing from the scope of the invention herein. Thus, it may, and probably will, prove to be the best practice to join, i. e., vulcanize, electronically seal, etc. the two identical halves or sheets of the tube 15, the ends of the sheets adjoining the radial slit 17 and the several seals 18 all in a single operation. Also, in that same operation or treatment the flap 19 may be concurrently afiixed or joined in the manner set forth above.

Adjacent to, and in close proximity with, the flap 19 an integral air tube 20 is provided in communication with the interior of the closure tube 15 to project outwardly from one side or sheet thereof. Upon the introduction of air under pressure at and through the air tube 20 by any conventional and well-known means, the closure tube 15 may be inflated. Due to the several seals 18, however, the localized portions of the tube 15 defined by these seals remain uninflated and relatively stiff causing these portions of the closure tube to be disposed centrally of the width of the tube when inflated, as shown in Fig. 3.

At and around the base of the air tube 20 a retaining means 21 is provided to receive and contain the folded tube 20 after the protective closure 15 has been fully inflated thereby locking the air within the tube 15 and preventing its escape. This means 21 consists of a sheet of resilient material preferably the same material as that of the tube 15 having a central opening 22 therein surrounding the base of the air tube 20. The outer or peripheral edge of the sheet 21 is immovably secured or afiixed, i. e., vulcanized or electronically sealed to the associated wall of the tube 15 whereby the remaining inward portion thereof forms a lip or flap which extends in the direction of the tube 20. Thus, when the tube 15 is fully inflated, tube 20 may be folded or crimped and then forced or stuffed under the lip of the sheet 21 to be there held and prevent the escape of air from the tube 15.

in view of the foregoing construction of the protective closure or tube 15, it is apparent that when the aircraft engine is unpacked or uncrated, tube 15 may be installed in the forward or intake end 11 of its housing to close or seal this intake opening. To this end the tube is positioned in the opening 11 with the ends thereof which define the radial slit 17 over or abutting the opposite sides of one of the spokes 13' of the spider 12 thereby positioning the several seals 18 of the tube 15 to overlie and be substantially coextensive with each of the remaining spokes 13. When the tube 15 is inflated through the air inlet tube 20, the defining inner and outer peripheral walls of the tube 15 snugly about and conform to the inner wall of the engine housing 10 and the outer peripheral surface of the annular bearing 12' or hub 13 respectively to completely fill and close the intake opening 11.

Since the seals or stiffened portions 18 of the tube 15 are disposed centrally of the width of the tube 15 as above described, the inflated or bulging portions of the tube 15 on opposite sides of the seals 18 extend substantially an equal distance on either side of the spider 12 so that the entire tube 15 is contained substantially within the outer or forward extremity of the housing 10. In this way any chance of the accidental or unintentional displacement of the tube from the opening 11 is virtually eliminated.

With the protective closure or tube 15 installed in the above manner, the engine may be assembled in the aircraft and all necessary connections established without danger of tools, hardware, etc., entering the housing through the intake opening 11. When the aircraft is finally assembled and removed from the shop or hanger to the airfield for its initial test run, the protective tube 15 may be readily deflated and removed from its installation in the forward end of the engine thereof. To this end a relatively small accessopening may be provided,

if desired, in the skin of the aircraft adjacent the loca-.

tionof the tube and more particularly .the flap 19 and the valve or air inlet 20 thereof. Following this general procedure, the internal operating mechanismis assured proremovably disposed in the opening in abutting contact with the frame to thereby fill and close the opening comprising a hollow longitudinally circular tube having unconnected ends disposed adjacent each other, a flap secured to one end of the tube and adapted to overlap the other end of said tube thereby completing an annulus, and

means for inflating the tube to expand it both radially and' laterally against the Wall of the housing and the frame, the ends of said tube being separable for removal from said opening by one of its ends.

2. The combination with a jet engine having a housing I with an air intake opening, a rotary shaft centrally disposed in the opening and a supporting frame comprising a concentric bearing forthe shaft and a plurality of radial arms interposed between and fixed to the bearing and housing, of an inflatable annular tube having adjacent closed ends and partial radially disposed internal partitions each to overlie one or the arms of said frame, said partitions creating intercommunicating compartments within the tube corresponding to and filling and closing the spaces between said arms, and means to inflate and deflate said tube to cause it to abut said frame and housing when inflated and permit it to be removedffrom the intake opening by one of its ends when deflated.

'3. The combination with the jet engine of an aircraft having a housing with an air intake opening to admit air to the engine, a rotary shaft concentrically disposed ,with an air intake opening, a rotary shaft centrally disposed in the opening, a journal for the shaft fixedly connectedto the housing by a plurality of spaced arms, of i an inflatable protective closure adapted to be removably disposed in-- the opening to fill and close it comprising a hollow longitudinally circular tube of airtight flexible material closed and sealed'at its adjacent ends, a flexible flap of the samematerial substantially greater in width 'a series of partitions extending transversely across the tube creating a series of interconnected compartments therein, one of said partitions to be'disposed over and in abutment with each of the spaced arms aforesaid to thereby locate a compartment between each pair of adjacent arms, and inflating anddeflating means attached to the exterior of the tube and connecting with one of said compartments for the inflation of all said compartments' whereby to expand the tube between the housing and the journal and its compartments between said arms,

. having a housing with an air intake opening to receive external air, a rotary shaft centrally disposed in the opening and a supporting frame having a journal for the shaft and a series of spaced arms fixedly connecting the journal to the housing, of a protective closure adapted to be removably disposed in the opening in abutting con- 1 thetic resin and having closed adjoining ends, a flap made in said opening and a frame having a journal for the shaft, said frame being fixedly secured to and supported by the wall of the engine housing defining the opening,

of an inflatable annular protective tube having adjoining closed ends and conforming in size and shape to the shape and area of the opening between the journal and housing adapted to be removably disposed in said opening in abutting contact with said frame, and means for inflating and deflating the tube whereby it expands to abut both the housing Wall and the journal of 'the'frame and to partially enclose the frame thereby completely filling and closing said opening when inflated and be removed longitudinally from said opening by oneof its ends when deflated.

4. .The combination with a jet engine having a housing .of the same resin as the tube connected to and extending from one end of the-tube adapted to overlap and partially surround the other adjoining end of said tube, and an inlet made of the aforesaid resin connected to the tube for the inflation and deflation thereof whereby it expands against the wall of the housing and the frame when inflated and may be removed from said opening by one of its ends when deflated.

References Cited in the file of this patent UNITED STATES PATENTS 539,568 Bride May 21, 1895 702,937 Franklin June 24, 1902 1,579,502 Blakeslee Apr. 6, 1926 2,409,433 Hunter Oct. 15, 1946 2,512,041 Steele June 20, 1950 FOREIGN PATENTS I 7,030 Great Britain Apr. 9, 1894 398,388 Great Britain Sept. 14. 1933 606,095 France -June 7, 1926 

